Ethynylpyridine-n-oxides and ethynylquinoline-n-oxides



ETHYNYLPYRIDINE-NQQXIDESAAND YL. QUINOLINE-N-QXIDES Jack H. Blumenth'al, Tlainfield, "N. 1., .assignor to Air uReduction Company, IucmporatecLNew YorlgiN. Y.,

a corporation of N evgsYfltk No Drawing. Application February 25, 1957 Serial No.641,799

is Claims. Cuzco-291 This invention relates to novel ethynylpyridine-N-oxides and ethynylquinoline-N-oxides and to methodsof making same. The compounds which are the subject of the present invention maybe represented by the following general form laS:

. CECR' and .. equations:

wherein R andR have the samemeaning as that given above "and-M is an alkali metal suchas sodium,l;lithium, potassium and the like. It will-be readily understood that the -natureof the alkali "metal acetylide employed will determine the *charaeterof ;the r ethynyl group subsututed m the pyridine N-oxide or quinoline' -N-oxide.

Thus, for example, ethynylpyridine-N-oxideand etliynylv quinoline N-o iide' may beprepared, respectively, by the "reaction' 'ofsodium aeetylide fi'NaCz- CH) andpyridine- N -o')'tide -01": quinoline N-ox idey phenylethynylpyr-idine N- oxide or phenylethynylquinoline-N-oxide maybe pre- 7 sodium .vinylacetylide' 2,874,162 Ratented .Feb. 17, 1 959 acetylide .NaCEC with pyridine-N-oxide l or quinoline-N-oxide; S-buten-lyne-pyridinerN-oxide may be prepared by the reaction of *dium which isliquid at reaction temperature and contains no functional or reactive groups. Other solvent media have not been found to be efiective tor this reaction. Thepreferred organic liquid sulfoxides may be designated by the formula:

wherein R and R are the same or different alkyl radicals or may be methylene groups which are bonded together through two or more methylene groups to form a ring str slctureas in tetramethylene sulfoxide. Suitable o g nic qu dsul ex de include d methyl u i xi diethyl sulfoxide, methyl ethyl sulfoxide, and tetramethyle ne sulfoxide; although dimethyl sulfoxide is preferred.

The temperature of the reaction will depend upon a variety of factors, including the specific reactants and the p rt cul l qui e g n e l oa eu d Gen a y, th

temperatur maytva fr bo the r ezing-p t of th re tin m ur to .a ax mum f a o C- 'A t mperatu e much abo e 0 unde i ab side eactions may occur andv the yields and conversions dec ease th e y- I i P er ed p cti to end e h reaction at a temperature of from about 5 to 20 C. Although elevated pressures may be used, there is no necessity for elevated pressures and atmospheric pressure is preferred.

Each of the reactants may be psed instoichiometric am un s i cc a c w th t equa n given a However, it has been found desirable to use an excess of the acetylide where an alkali metal. acetylide (MCECH) is the reactant and to use equimolar amounts where substituted acetylides are employed. v i

The following specific example will further illustrate this invention:

EXAMPLE Prepartion of ethynylpyridine-N-oxide of the sodium acetylide had been added, the reaction temperature was -.permi tte d to come to room tempera ture while the mixture was stirred. The reaction mixture was neutralized with coldydilute hydrochloric acid, and the resulting mixture was filtered. The filtrate was extracted, portionwise, with 400 cc. of ethyl ether. The ether extract was dried over magnesium sulfate and the ether distilled ofi. The residue was recrystallized from carbon tetrachloride The compound, ethynylpyridine- N-oxide, which was obtained had a melting point of 112- 115 -C. and was in the form of yellow crystals which turned brown on standing. The compound was about 91% pure based on both acetylenic hydrogen and nitrogen analysis:

Calculated for C H NO-CECH: N, 11.65%; CECH, 20.8%. Found: N, 1 0.7%;CECH, 19.0%.

It will be understood that the foregoing example is merely illustrative and that various modifications thereof can be made without departing from the spirit and scope of this invention. For example, as more fully pointed out hereinabove, various other ethynylpyridine-N-oxides may be obtained by substituting other alkali metal acetylides for acetylide of the example; ethynylquinoline-N-oxides are obtained in similar manner; either pyridine-N-oxide or quinoline-N-oxide or alkyl or aryl substituted quinoline-N-oxides or pyridine-N-oxides may be employed; any of a variety of liquid organic sulfoxides are suitable as the reaction medium; and still other variations will suggest themselves to those skilled in the art.

The ethynylpyridine-N-oxides and ethynylquinoline-N- oxides of this invention are suitable for a variety of uses, such as precursors for the preparation of corresponding vinylpyridine-N-oxides and vinylquinoline-N-oxides. For example, vinylpyridine-N-oxides may be obtained by the semi-hydrogenation of ethynylpyridine-N-oxide in the presence of a suitable hydrogenation catalyst such as palladium, nickel or platinum. In like manner, vinylquinoline-N-oxides may be obtained by the semi-hydrogenation of ethynylquinoline-N-oxides. The metal hydro genation catalyst may be supported on a carrier such as charcoal, silica, activated alumina and the like. The vinylpyridine-N-oxide and vinylquinoline-N-oxide derivatives, which are thus obtained, may be used for the preparation of polymers and copolymers as described in United States Letters Patent No. 2,749,349 to Francis E. Cislak, issued June 5, 1956. The ethynylpyridine-N- oxides and ethynylquinoline-N-oxides may also be used as an intermediate for the preparation of pharmaceuticals and pesticides such as fungicides, insecticides, herbicides; etc. Still further, the novel ethynylpyridine-N-oxides and ethynylquinoline-N-oxides of this invention may be used as additives for chlorinated hydrocarbon solvents such as trichloroethylene, perchlorethylene and the like to stabilize such chlorinated hydrocarbon solvents from decomposition due to exposure to heat and light, and to inhibit the corrosive efiects of the degradation products of such decomposition. For example, small amounts, i. e. about 0.01 to 1.0 percent by weight of an ethynylpyridine-N- oxide or ethynylquinoline-N-oxide may be added to a chlorinated hydrocarbon solvent, e. g. trichlorethylene, to obtain these stabilizing eflfects.

The invention is not to be limited except as defined in the appended claims.

What is claimed is:

1. Ethynylpyridine-N-oxides and ethynylquinoline-N- oxides represented by a formula selected from the group consisting of R CEGR' and CECE

wherein R is a member of the group consisting of hydro gen, an alkyl radical containingfrom 1 to 4 carbon atoms, and a monocyclic hydrocarbon aryl radical, and R is a member of the group consisting of hydrogen, lower alkyl, lower alkenyl, monocyclic hydrocarbon aryl.

2. Ethynylpyridine-N-oxide.

3. Phenylethynylpyridine-N-oxide.

4. 3-buten-l-yne-pyridine-N-oxide.

5. Propyne-l-pyridine-N-oxide.

6. The process for preparing ethynylpyridine-N-oxides and ethynylquinoline-N-oxides represented by a formula selected from the group consisting of CEOR' and and

with an alkali metal acetylide of the formula MCECR' where M is an alkali metal in the presence of a liquid organic sulfoxide.

7. The process as defined in claim 6 wherein said liquid organic sulfoxide is dimethyl sulfoxide.

8. The process for preparing ethynylpyridine-N-oxide which comprises reacting pyridine-N-oxide with an alkali metal acetylide of the formula MC::CH, wherein M is an alkali metal, in the presence of a liquid organic sulfoxide.

9. The process for'preparing ethynylpyridine-N-oxide as defined in claim 8 wherein said alkali metal acetylide is sodium acetylide and said liquid organic sulfoxide is dimethyl sulfoxide.

10. The process for preparing phenylethynylpyridine- N-oxide which comprises reacting an alkali metal phenylacetylide with pyridine-N-oxide in the presence of an organic liquid sulfoxide.

11. The process for preparing 3-buten-1-yne-pyridine- N-oxide which comprises reacting an alkali metal vinyl acetylide with pyridine-N-oxide in the organic liquid sulfoxide. v

12. The process for preparing propyne-l-pyridine-N- oxide which comprises reacting an alkali metal methyl acetylide with pyridine-N-oxide in the presence of an organic liquid sulfoxide.

presence of an 13. The process for preparing phenylethynylpyridineoxide as defined in claim 12 wherein said liquid organic N-oxide as defined in claim 10 wherein said liquid organic sulfoxide is dimethyl sulfoxide. sulfoxide is dimethyl sulfoxide.

14. The process for preparing 3-1 auten-1-yne -pyridine- References Cited in the file of this Patent N-oxide as defined in claim i1 wherein said liquid organic 5 UNITED STATES PATENTS sulfoxide is dimethyl sulfoxide.

15. The process for preparing propyne-l-pyi-idine-N- 2,749,349 Cislak June 5, 1956 

1. ETHYNYLPYRIDINE-N-OXIDES AND ETHYNYLQUINOLINE-NOXIDES REPRESENTED BY A FORMULA SELECTED FROM THE GROUP CONSISTING OF 